This is a fast-track proposal to develop a GMP biocompatible microstimulator for implantation into humans for treating chronic pain. The feasibility of using an implanted wireless microstimulator for the treatment of chronic pain will be tested in Phase I. In Phase II we will develop a more sophisticated GMP quality microstimulator for use in humans. The footprint and platform of the microstimulator will be the same in both Phase I and Phase II. The internal circuitry and device integration will be fully developed in Phase II. The conditions of neuropathic pain and chronic inflammatory pain create a large medical and societal burden that affects over 50 million people in the US. Current treatments include pharmacological agents and electrical stimulation techniques. Existing pharmaceutical treatments lack long-term efficacy or have dose limiting side effects. Neurostimulation techniques such as transcutaneous and percutaneous electrical stimulation (TENS and PENS) lack such side effects and have therefore become popular alternative therapies. While TENS is mildly efficacious, PENS treatments seem to be far more efficacious. However, PENS is highly inconvenient and invasive, often leaving the patient unable to receive treatment when needed most. To address these weaknesses of current electro-stimulation therapy, MicroTransponder has developed a tiny implantable wireless microstimulator device (1mm diameter and less than 250 um thick) that may have the efficacy of PENS without any of the inconveniences. This device is powered and controlled by near field radio frequency (RF). The device is capable of directly stimulating peripheral nerves and can be controlled by the patient to deliver therapeutic stimulation as needed. This device should be an inexpensive, safe, and convenient solution to patients with chronic pain of different origins. In Phase I, we will test efficacy of the device for complete suppression of mechanical hyperalgesia in animal models of inflammatory pain (Freund's adjuvant, CFA) and neuropathic pain (Bennett model). In Phase II we will improve the circuitry, integration, and encapsulation of our device so that it is more appropriate for human use and then manufacture the device under GMP controls. We will then validate the newly manufactured device in conjunction with FDA guidance. At the end of Phase II, we will be prepared to file an investigational device exemption (IDE) for human clinical testing of our device. In follow-on Phase III studies we will test for efficacy in humans. Once efficacy in humans is proven, we will develop the device for full commercialization.